SCoupe

lolfof

sc3boost

why would it take for ever to spool the big turbo?

the only reason for the big turbo will be to give it a bigger top end, so if it does'nt spool untill 5k rpm thats cool.

what i was thinking as long as yopu don't use a tiny turbo in front of the big one the exaust that comes out should have enough pressure to spool the second one.

and shuld'nt the waste gate on the first turbo prevent it from over spooling while sending the unused exaust to the second turbo.

i'm not arguing i'm just trying to understand why it would'nt work???

Gamer

Look at it this way.

If it would work, (and the gains were worth it) then it would have been done by now....

ATL-SC

the way i see it is if the big one spools at 5k but it takes till 3k to have full bost on the small one then you divert the extra gas from the waste gate into the big one it want spool untill 7-8k

oops thats past redline and useless

CleanSC

Many good points have been covered with regards to the extra complication, hassle, and HEAT in a setup like this.

If a particular type of squential forced induction to reduce lag is what we're bench racing about, consider a twincharged super/turbocharger setup.

This has actually been done and is much less impractical. Your supercharger gives you your low end on the front of the motor, and your big turbo takes over on the back end.

Sttill a pain in the ***, tho.

sc3boost

twincharging is a *****, i cheaked it out a couple months ago, it's not for me.

but i see what you guys are saying, i'll go try to think of some other impossible thing to do to a car

it was just an idea anyway.

FortuneLS

how many people on here have upgraded twin turbo set-ups, all i see are big single turbo set-ups, i plan on running the hks gt2835 twin turbo set up, it is good for around 700 whp, and if i decide i need more power a twin gt3540 set-up will send me over 1000whp. twin turbos rock

sc300tt

You think twin-charging is bad compared to the setup you described? Not to mention that a nice positive displacement blower like a Whipple will give you a much better setup than any "small, pre-spool turbo" could, given the size constraints within the engine bay. But in the end, Nitrous gives the same effect for far less money and hassle.

Umm....A single turbo setup will make just as much power with the same spool characteristics as big HKS twins, for far less money. The only advantage the twins offer is in the "bling" dept, which they do quite well.

sc3boost

hey i don't mean to change the subject but i don't want to start a whole new thread for this.

i just found a deal where i get a supra front clip(1jz) with a 5speed tranny for $2500.00 shipped to my door in f.t lauderdale.

problem is i heard that everything is different on a supra clip compared to a soarer clip.

did any of you guys use a supra clip instead of a soarer for your swap, if you did or know someone who did pm me please, i don't want to loose the deal.

sorry for changing the topic i don't think this question deserved another thread.........

Dramon

1) thats so much weight in turbos.
2) have fun fitting two turbos and a t88h.
3) with advances in turbos a ball bearing single can cut down on lag a lot.
4) another thing people tend to forget is that your mani plays a HUGE role in how much lag you have. a properly designed mani can cut down spool by a few hundred rpms easy.
5) to setup a sequential TT system thats not stock would be a huge PITA. Not only do you have to fit everything in the engine bay you need to figure out some sort of prespool if you want any sort of linear powerband. There's a reason you dont see sequential twin turbo setups much anymore and thats complication.

FortuneLS

[/QUOTE]Umm....A single turbo setup will make just as much power with the same spool characteristics as big HKS twins, for far less money. The only advantage the twins offer is in the "bling" dept, which they do quite well.[/QUOTE]

i am aware that big singles can produce just as much, in most cases more, than a twin set-up, and in the "bling" dept. they have a huge advantage. you used to have a twin turbo set-up didnt you?, and now you run a single set-up, i know you switched for a reason and that you know what your talking about, i was just saying that if you want to be different do a twin set-up cause you just dont see too many around anymore, mostly big single turbos. i want to do a twin set-up even though it costs more, i think the hks gt2835 kit is like $8000 now isnt it? not calling you a liar, i just find it hard to believe that a big t88h turbo will spool just as quickly as two smaller gt2835s

qtb33

FYI pressure dosn't work like this. You cannot run a system with one turbo at 8psi and another at 10psi and claim you have 18psi. In fact if you do this, you'll only end up with 8psi and one dead turbo that was KIA fron huge amounts of compressor surge.

If you run twins or more than one turbo heres what you'll generally see. (I'm just making number up here, but you should get the idea)

Turbo 1 running (lets say) 8psi at 20 lbm/min
Turbo 2 running the same 8 psi and the same 20 lbm/min

Final results will be 8 psi and 40lbm/min.

Now if you run them in series or parallel is where you are going to see differences in pressures in turbos but once full boost is attained I'll bet good money they run the same pressures.

PHLSingle

Basically you guys are talking about compound turbo charging, for the most part. I did see some other posts about sequential...and did I see someone mention 3 turbos?!

Diesel guys have been doing this for years:
http://www.piersdiesel.com/DodgeTwins.htm

And search on supraforums...there is a thread PAGES long on this...

FortuneLS

caterpillar manufactures diesel twin turbos also, i used to work at a mack truck dealership in the body shop and we had a kenworth come in that had a cat twin turbo engine in it with a set up just like the one on that website where the downpipe from the first turbo leads into the turbine inlet of the second turbo, its a bizzar set-up i think

sc300tt

Yes, I used to have the HKS twins. I only bought them for the bling factor, but just got tired of dealing with them. A comparable single normally has a small theoretical advantage, but in real world applications, it has never been anything measurable. Two smaller turbos have a smaller moment of inertia than a comparable single larger one, but since most of the work a turbo does is the actual compression of air, not overcoming the moment of inertia, this becomes a moot point.